Mutation of the immunophilin-like FK506-binding protein TWlSTED DWARF1 （FKBP42/TWD1） causes dwarf and twisted-organ phenotypes in Arabidopsis. However, the function of FKBP42 is not fully understood at the molecular...Mutation of the immunophilin-like FK506-binding protein TWlSTED DWARF1 （FKBP42/TWD1） causes dwarf and twisted-organ phenotypes in Arabidopsis. However, the function of FKBP42 is not fully understood at the molecular level. Using genetic, physiological, and immunological experiments, we show here that FKBP42/TWD1 is necessary for brassinosteroid （BR） signal transduction. The twdl mutant showed reduced BR sensitivity in growth responses and activation of the BZR1 transcription factor. However, twdl showed normal responses to an inhibitor of BIN2/GSK3, suggesting that twdl has a defect upstream of BIN2 in the BR signaling pathway. In vitro and in vivo assays showed that TWD1 interacts physically with the kinase domains of the BR receptor kinases BRI1 and BAK1. TWD1 is not required for normal localization of BRI1-GFP to the plasma membrane or for activation of the flagellin receptor kinase FLS2. Our results suggest that FKBP42/TWD1 plays a specific role in the activation of BRI1 receptor kinase.展开更多
文摘Mutation of the immunophilin-like FK506-binding protein TWlSTED DWARF1 （FKBP42/TWD1） causes dwarf and twisted-organ phenotypes in Arabidopsis. However, the function of FKBP42 is not fully understood at the molecular level. Using genetic, physiological, and immunological experiments, we show here that FKBP42/TWD1 is necessary for brassinosteroid （BR） signal transduction. The twdl mutant showed reduced BR sensitivity in growth responses and activation of the BZR1 transcription factor. However, twdl showed normal responses to an inhibitor of BIN2/GSK3, suggesting that twdl has a defect upstream of BIN2 in the BR signaling pathway. In vitro and in vivo assays showed that TWD1 interacts physically with the kinase domains of the BR receptor kinases BRI1 and BAK1. TWD1 is not required for normal localization of BRI1-GFP to the plasma membrane or for activation of the flagellin receptor kinase FLS2. Our results suggest that FKBP42/TWD1 plays a specific role in the activation of BRI1 receptor kinase.
